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Finding the Fourth Proportional to 678.81, 1,018.11 and 191.79

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Solution

The fourth proportional to 678.81, 1,018.11 and 191.79 is: 287.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.81 : 1,018.11 = 191.79 : x
  2. Step 2: Convert to fraction form
    678.81/1,018.11 = 191.79/x
  3. Step 3: Cross multiply
    678.81x = 1,018.11 × 191.79
  4. Step 4: Simplify right side
    678.81x = 195,263.32
  5. Step 5: Solve for x
    x = 195,263.32/678.81
  6. Step 6: Final answer
    x = 287.66

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.